United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROO/R06-87/021
June 1987
&EPA Superfund
Record of Decision:
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-
TECHNICAL REPORT DATA
(Pftrut fftld '"lInJCtlO"S 011 tht ,tV,1ft IHfon l:o,""f'li1ll)
,. I'I"Ol'lT NO. /2. 3. RECI"ENT'S ACCESSION NO.
EPA/ROD/R06-87/021
.. TIT!.I ANO SUITIT!.' 5. I'II'ORT DATI
SUPERFUND RECORD OF DECISION June 26, 1987
Highlands Acid Pit, TX 8. '1I'I~Ol'lMINO Ol'lOAN'ZATION CODE
Second Remedial Action - Final
7. AUTMOI'ICSI 8. I"EI'IFOI'IMINO OROANIZATION REPORT NO.
v. PERFORMINO OROANIZATION NAME AND ADDRESS 10. PI'IOORAM EI.EMINT NO.
1'0 CONTRACT/ORANTNO.
12. SPONSORING AOENCV NAME AND ADDRESS 13. TVPE OF RE'ORT AND PERIOD COIIEREO
U.S. Environmental Protection Agency Final ROD Report
401 M Street, S.W. 1.. SPONSO'''NG AOENCY COOE
Washington, D.C. 20460 800/00
15. SU"l..eMENTARV NOTES
18. A8STI'IACT
The Highlands Acid Pit site is located 16 miles east of Houston on a 6-acre peninsula
in Harris County, Texas. The site is bordered on the west and south by the San Jacinto
River, on the north by a wooded area, and on the east b~ a i~nd pit. The si te lies
within the lO-year flood plain and has subsided 2.4 feet"since 1964. An unknown
quantity of industrial waste sludge was disposed of at the site in the 1950s. The
sludge is believed to be spent sulfuric wastes from a refinery process. The June 1984
Record of Decision, addressing the source of contamination, was inadequate to evaluate
the full extent of ground water contamination. The primary contaminants of concern
addressing ground water include VOCs and heavy metals.
The recommended remedial action includes a no action remedy with long-term ground
water and surface water monitoring since the contaminants of concern were not detected
above criteria levels. The capital cost for this monitoring program is $4,700 with
annual O&M of $6,980.
17. KIV WO"'D8 AND DOCUMENT ANAL VIIS
.. OI8C""PTO"" b.IOINTI~IE"'S/O'IN ENOIO TE"'MS 4:. COSA TI FieldlGroup
Record of Decision
Highlands Acid Pit, TX
Second Remedial Action - Final
Contaminated Media: gw, sw
Key contaminants: VOCs, heavy metals
11. OIST"'IIUTION STATIMENT 11. SECU"'ITY CLASS (Thu R.port) 21. NO. OF PAOiS
None 37
20. SICu",.TY C!.ASS (TI'il POPI 22. p"'lce
I'. ,- 2220-1 (R... 4-77)
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ABBREVIATED RECORD OF DECISION
HI GH-LANDS AC I D PIT
GROUNDWATER OPERABLE UNIT
Site:
Highlands Acid Pit site is located 16 miles east of Houston and 1.4 miles
west of Highlands, Texas.
Documents Reviewed
I have reviewed the following documents to determine the need for corrective
action for the groundwater operable unit at the Highlands Acid Pit site:
o Highlands Acid Pit Site Record of Decision for the source operable
uni t -- dated June 25, 1984.
o
Summary of Remedial Alternative Selection -- dated January 1984.
o Feasibility Study: Groundwater Management Evaluatio~~ Report for Highlands
Acid Pit Site; Highlands Texas -- dated January 1986; Camp Dresser and McKee.
o Groundwater Study Report for Highlands Acid Pit -- dated April 1987;
Camp Dresser and Mckee.
o Operating Plan for Remedial Action Project, Highlands Acid Pit;
Highlands, Texas -- dated February 26, 1987; Chemical Waste Management,
Incorporated, Volume 1, Sections 4 & 5 and Appendix E.
o Staff summaries and recommendations.
'-
o Responsiveness Summary
The "SuRlllary of Remedial Action Selection" is attached hereto, incorporated
herein by preference, and made a part of this Record of Decision. This
attached docu~t sum.arizes the remedies considered and is the basis for
-my decision.
Description of Selected Remedial Action
o Directly upon completion of the Source removal action, a long term monitoring
program shall be initiated for the shallow and next lower aquifer and for the
surrounding surface water bodies--water and sediment samples.
o
If, after source removal, monitoring reveals that the site continues to
release contamination such that the adjoining surface waters or deeper
ground~ter is adversely impacted, then further action will be considered.
If no trend toward adverse impacts is detected, delisting will be pursued.
--
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v
to
2
Declaration
Consist~nt with the Comprehensive Environmental Response. Compensation. and
Liablity Act of 1980 as amended by Superfund Amendments and Reauthorization
Act of 1986. and the National Contingency Pl an. I have determined that long
term monitoring of groundwater and surface waters will provide adequate
protection of public health, welfare. and the environment.
The state of Texas has been consulted and agrees with the approved remedial
action for the groundwater operable unit. The activities outlined in the
1984 ROD for source control operation and maintenance are incorporated into
the selected remedy for the groundwater unit. In addition, Grennel Slough,
Clear Lake, and the sand pits will be routinely monitored for buildup of
contaminants. If an increase in contaminants from the site is detected
during a monitoring period, an investigation will be initiated to determine
the need for future action. For such case, a Record of Decision must be
prepared for any future remedial action.
-
... '!-
C:.2'-~7
,,,,,,/ .
k~~ R '£:7 r:~ ~.
Date
Robert E. Laytor'l, Jr., P. E.
Regional Administrator. Region VI
-
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Summary of Remedial Action Selection
Highlands Acid Pit
Groundwater Operable Unit
Highlands, Texas
April 1987
Site Location & Description
The Highlands Acid Pit site is located in a sparsely populated area of Harris
County, 16 miles east of. Houston and 1.4 miles west of Highlands, Texas. The
location of the site is shown in Figures 1 & 2. Bordered by a wooded area
to the north, Grennel Slough to the west, Clear Lake to the south, and flooded
sand pits to the east, the Highlands site is situated on a 6 acre pennisu1a
within the 10-year flood plain of the San Jacinto River. Land use in the
surrounding area is 24% residential, 20% surface waters, 16.4% mixed forest,
7.6% forested wetland, and 7.6% industrial.
The average elevation of the site is approximately 5 to 10 feet above M~an Sea
teve1 (MSL). Dense vegetation covers the site except for the bare area in the-
center of the site, bel ieved to be the primary dumping 'area. Although drainage
is primarily south into Clear Lake, there fs signifi"fanf drainage west into the
San Jacinto River and east into the sand pits. Nearly 5 feet of subsidence has
been recorded at the site between 1890 and 1973. The low relief of the surrounding
area results in periodic flooding onsite. As subsidence continues, the instances
of flooding are expected to increase.
Site History
The Highlands Acid Pit site was used for the disposal of an unknown quantity of
industrial waste sludge, believed to be spent sulfuric acid from a refinery
process, during the early 1950's. The Summary of Remedial Alternative Selection,
dated January 1984, [future references: 1984 ROD Summary], outlines the site
history prior to 1984. The June 24, 1984 Record of Decision (ROD) dealt with
the source of contamination at the Highlands Acid Pit site. The 1984 ROD remedy
included the following: l)excavate waste and contaminated 50i1 over a 2.41 acre
area, down to the water table; 2}transport excavated material to a permitted
. class 1 dispoSIJ flcility; 3} backfill the area with clean fill; 4)insta11 a
groundwater monitoring system; 5) perform site maintenance and groundwater
monitoring for a 30 year period~ The remedial design of the source control
was approved December 4, 1985. Mobilization for the source control operable
unit remedial action was initiated in February 1987.
The majority of information presented in the 1984 ROD Summary was adequate for
identifying groundwater reclamation alternatives for the Groundwater Feasibility
Study (FS) dated January 1986. However, information on the, subsurface environ-
ment was inadequate to evaluate any corrective action for the shallow aquifer.
The integrity of the clay aquitard separating the upper and middle aquifers and
the full extent of groundwater contamination were not investigated prior to the
Groundwater Study (GWS) completed in April 1987.
.,.
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.
:,
.
.
"
.
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SCAU .. -UI
..
fiGURE 1: SITE LOCATION HIGlANOS ACID PITS
.
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FIGURE
2:
LOCATION MAP OF HIGHLANDS ACID PIT
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4
CURRENT SITE STATUS
The 1984 ROO Summary presents the findings of the Highlands site Remedial
Invest.igation (RI)/Feasibility Study (FS) in reference to surface water levels,
alluvium deposits, aquifer formations, water well inventory, nature and distri-
bution of wastes at the site, and impact assessments for exposure of wastes to
the hydrologic system. Information relevent to the groundwater operable unit
is summarized in the following subparts. Although reported in the Groundwater
Study, this information originated in previous investigations.
Geology
The local near-surface geology at the Highlands site is comprised of three sand
intervals separated by two clay strata, Figure 3. The upper sand layer, recent
meanderbelt alluvial sediments, varies in thickness from 18.5 to 26.0 feet.
The Beaumont Clay Formation, underlying the upper sand, forms alternating
layers of clay and sand. The clay aquitard directly beneath the upper sand is
30 feet thick across the entire.site area. This clay interval grades from a
slightly silty clay at the alluvial contact to a silty sandy clay at -45 feet
MSL. A 23 to 26 foot sand layer, the middle sand, underf;es the clay aqu;tard.
A second clay aquitard, 25 feet thick, separates the middle sand from a lower
sand interval, 14 to 18 feet thick.
~
Hydrogeology
The permeability of the upper alluvial sand ranges from 4.0 to 8.0 ft/day.
Groundwater elevations in the upper sand are strongly correlated with the level
of the San Jacinto River, indicating that the river and the alluvium are hydrau-
lically connected. Due to this connection, groundwater flow varies with the
level of the river. At high tide, the primary flow direct10ns are east toward
the sand pits and south toward Clear Lake. The groundwater flow to the west,
toward the San Jacinto River, is small. At low tide, similar flow patterns are
evident. However, the groundwater elevations and gradients are lower and there
is some inland flow to the southern portion of the site. Groundwater elevations
for wells completed 1n the upper sand range from 1.64 to 2.25 MSL.
Limited infonlatton 4s available for the middle and lower sands. Only one
well was completed 1n the middle sand. The groundwater elevation in this well
is -1.53 feet MSL. TWQ wells completed in the lower sand show groundwater
elevations ranging from -57.02 to -64.25 feet MSL.
_.
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..
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FIGURE 3:
HIGHLANDS ACID PIT SITE NEAR-SURFACE GEOLOGY
.1.
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6
Groundwater Study Investigation (GWS)
In March 1985, a groundwater study was initiated to evaluate the potential
for migration of shallow yroundwater contaminants once the source of contamination
is remaved. In November 1985, fieldwork at the site included redevelopment
and repair of existing monitoring wells. New monitoring wells were also
installed in the upper aquifer. To establish the extent of contaminant
migration, a second phase of sampling was completed in July 1986. Additional
surface water and sediment samples were taken, as well as samples from the
upper and middle aquifer and the clay aquitard. Figure 4 shows onsite sampling
locations referenced in the GWS. The legend for this figure cross-references
the well labels used in previous investigations.
The nearest private well, screened in the middle aquif~r 1/2 mile north of
the site, was also sampled. This well is not used for drinking water and,
based on the limited middle aquifer information available, is located up
gradient from the site. Figure 5 is a location map of private wells within
a 2 mile radius of the site. Well 7 is the only middle aquifer well. All
other wells are screened in the deeper aquifer. From the well survey of this
area, the shallow aquifer is not considered a source of potable water.
Extent & Ma nitude of Contamination: Sampling result~'show high
concentration eve s of vo ati e organics and heavy metals within the upper
sand saturated zone (shallow aquifer). Chosen on the basis of toxicity,
concentration, and persistence, the contaminants of major concern include
benzene, pyridine, arsenic, cadmium, chromium, and lead. Table 1 includes
the range of concentrations for each of these contaminants as sampled over
the 9 shallow aquifer wells onsite. Standards used to assess health and
environmental risks are also listed. Water Quality Criteria (WQC) are used
for surface water impacts and Maximum Contaminant levels (MCl) are used for
drinking water aquifer determinations. With the exception of pyr'idine, all
high concentrations were detected in well UA5 (Figure 4), located in the most
contaminated area onsite. The high concentration of pyridine was detected
in we 11 UAl (F i gure 4). .
Although organics & heavy metals have saturated the transition region between
the upper sand and the underlying clay aquitard, contaminants of concern were
not detected in the middle aquifer. The contaminant concentrations detected at
various depths within the clay aquitard are for two referenced boring locations
ASl and AS2, Tables 2-and 3 respectively. Benzene was found in decreasing
concentrations up to a depth of 8 feet in the clay aquitard while pyridine was
not detected beyond a 3 foot depth. Maximum concentrations of both benzene and
pyridine reach only 3 feet in each of the boring samples. Inorganics of concern
were found at background levels within the clay aquitard.
With the exception of chromium, contaminants of concern were not detected in
the San Jacinto River, Grennel Slough, Clear lake, or the sand pits. Total
chromium was detected at 0.005 mg/l in Grennel Slough, well below the WQC of
0.05 mg/l for Cr+6 and 170 mg/l for Cr+3. Sediments sampled at the same
surface water locations do not demonstrate levels of concern when compared
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Oescri tion
LEGEND for FIGURE 4
Samp 1 i n9 Number
Groundwater Stud
Previous Investi ations
Upper AqUl fer
Middle Aquifer
Deep Aquifer
Surface Water Sampling
S~dlmen~ Sampliny
. Aquitard S.,l~ng-
..
UAI
UA2
UA3
UA4
UA5
UA6
UA8
UA9
UAIO
MA2
OAI
DA2
SWI
SW2
SW3
SW4
SDI
S02
SD3
SL4
ASl
AS2
MW-1B
NW-2B
MW- 3B
MW-4
MW-l
MW-5
MW-6
.. e,.
MW-2A
MW-IA
MW-3A
A-3
A-4
A-IO
A-6
A-3
A-4 (EHA) S-2 (TOWR)
A-10(EHA) 5-1 (TDWR)
A-6
B-7
B-3
7
Comments
TOWR we 11
TOWR well
TOWR we 11
New well
New we 11 .
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.
..._L
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UM
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CLEAR LAKE
fIGURE 4: SAMPLE LOCATIONS
-------
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FIGURE 5
WI~.&.OC&TION
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('
TAB lE 1:
COKrAHlNAKrS Of CONCERN IN THE SHAll~ AQUIfER
(sampling events from 11-85 through 6-86)
COKrAHlNAKrS
fOf RANGE OVER 9 WEllS CLEAN WATER ACT SAFE DRINKING WATER ACT
CONCEMN ONS IT E Water Quality Criteria Maximum Contaminant levels
,
Benzene NO - 210.0 [0.66] 0.005
Pyridine NO - 3.2 None Established None Established
Arsenic NO - 1.2 2.2 ng/1 0.05
Cadmi~ NO - 0.019* 0.01 0.01
Chromium. total 0.018 - 2.699
Chromi um. Cr +6 0.05 / 0.05
Chromium. Cr+3 170.0 None Established
lead 0.005 - 0.118 0.05 ~ 0.05
.
.,
NOTES: All concentrations in mg/l unless stated otherwise.
NO = No Detection at HSl Detection limit
[] = Detection limit Value
* Well directly beneath site was sole detection--all others showed ND.
~
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TABLE 2: BORING AS-1 SAMPLING SUMMARY
(Concentrations in ug/kg)
Sarnp1es for 11/85
Dep~h (feet) 0.0-5.0 , 0.5-1.0 1.0-1. 5 1. 5-2.0 2.0-2.5
Bfnzene 430 ' 570 13 3.J 1HOO
Pyridine 16000,B 7000 NO 3400 13000
Samp1es for 6/86
Depth (feet) 2.5-4.5 4.5-6.5 6.5-8.5 8.5-10.5 10.5-12.5 12.5-14.5 14.5-16.5 16.5-18.5 18.5-20.5 20.5-22.~
Benzene 98 NO NO NO NO 11 4.J.B 2.J.B NO NI)
Pyridine NO NO NO NO NO NO NO NO NO NO
Arsenic 3100 12000 NO NO 6100 4500 3000 5400 UOO 31UU
Cadrni urn NO NO NO NO NO NO NO NO NO NU
.
.
Chromium 37000 37000 40000 44000 35000 27000 28000 26000 31000 30uuu
., .
I
lead 13000 15000 22000 22000 16000 14000 17000 27000 13000 890U
t--
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TA6LE 3: BORING AS-2 SAMPLING SUMMARY
(Concentrations in ug/kg)
S~V'~f for 11/85
Oeptn red) U.O-~.O 0.5-1.0 1.0-1.5 1.5-2.0 2.0-2.5
.
Benz.ne 44 52 NO NO 230
PYf1ai ne 27UU 970 NO NO 4700
S~plt:s 6/ti6
Uevtn (feet) 2.~-4.5 4.5-6.5 6.5-ti.5 8.5-1U.5 10.5-12.5 12.5-14.5 . 14.5-16.5 16.5-18.5 18.5-20.5 20.5-22.5 22.5-24.~
~nzene 5tiO 350 72 NO NO NO NO NO NO NO NO
PYf1ai Ill:! NO NO NO NO NO . NO NO NO NO NO ND
Arsenic NU 10600 NO 4100 8400 4900 NO NO NO 8400 NO
Caamium NO 29lJU NO 26UU 2UOO [1400] 1200 NO 1300 2900 1900
11
Chromi liD 220UO 16000 27000 26000 20000 17000.. 8200 18000 20000 25000 2500n
Leaa 2ti5UO 21800 lUlOU 13100 21400 20500 16300 10100 15900 18400 7UUU
.,
......
N
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13
.
Transport & Impact of Contamination: Upon completion of the source removal
action, surface water contamination from runoff will be eliminated. The
source of the contaminant loading to the upper aquifer will also be removed.
Migration pathways wil} then include vertical movement of shallow groundwater
through the underlying clay aquitard to deeper groundwaters and lateral
movement of shallow groundwater to surface water bodies.
The natural flow of groundwater cleanses the pore spaces within the shallow
aquifer over time. Attenuation of contaminants down to nondetectible levels
within the upper aquifer should take about 350 years. This time estimate is
based upon the retardation factor of benzene and the properties of the aquifer
itself. Organics should ittenuate throughout the clay aquitard horizontally
and vertically while inorganics are caught in sediments of the top portion of
the clay aquitard. If organics reach the middle aquifer, contaminants could
be detected before levels of concern are reached.
Groundwater flow to surface water bodies will continue to carry some
contaminants to the surface environment. However, the heavy metals are not
mobile at the pH of the transition region for groundwater flow to surface
water bodies and the organics are volatile upon contact with the atmosphere.
In view of the dynamics of the river and the properties of the contaminants,
the San Jacinto River should not be affected. eo
ENFORCEMENT
Only one potentially responsible party, the landowner, has been identified.
The identified party does not have the financial assets to pay for any
remedial action pertaining to the groundwater at the site. Attempts to
identify the generator(s) of the waste have been unsuccessful. Therefore,
the Environmental Protection Agency, Region VI office, recommends that the
Fund be used for the groundwater operable unit remedial action at the Highlands
Acid Pit site.
-.
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14
. -
ALTERNATIVES E~LUATIO~
The p.xposure to risks "associated with contaminants present in the shallow
groundwater. upon completion of the source removal. form the basis for the
following objectives of the Groundwater Operable Unit: .
o
Characterize contaminant migration to surface waters. area
. environment. and deeper groundwaters.
o
Determine potential impacts to potential receptors.
o
Evaluate the need for groundwater corrective action at the
Highlands site.
The groundwater FS identified four remedial alternatives for groundwater
reclamation prior to fulfilling the above objectives. Although these remedial
alternatives were developed to eliminate or reduce the risks of future exposure
to shallow aquifer contaminants. these risks were not entirely established
due to the lack of data. The GWS was initiated to meet the above objectives
by providing the information required to effectively evaluate those remedial
alternatives generated in the groundwater FS. Furthermore. such information
would ensure a reliable evaluation of the need for groundwater corrective
action. The GWS results indicate that the no action alternative should be
considered in t~e final screening process. e
All remedial alternatives are to be screened based upon the results of the
GWS in conjunction with the criteria outlined in the Superfund Amendments and
Reauthorization Act (SARA) and the National Contingency Plan (NCP):
o
Effectiveness
o
Imp1ementability
Cost
o
Effectiveness is evaluated on a basis of protectiveness, reliability, and
reduction.in toxicity, mobility, or volume. Applicable, Relevant, and
Appropriate Requirements (ARARS) of other Federal and more stringent State
laws are also used to determine the effectiveness of a remedy. Implementa-
bility involves technical feasibility, availability of required resources,
and administrative feasibility (time frame of implementation and level of
operator skill/lt~.n~ion). Total cost includes capital, replacement, and
operation and mafntenance.
Table 4 is a summary of the initial screening of available alternative
options as determined in the groundwater FS. Table 5 outlines the costs
associated with each alternative developed after the initial screening.
The no action alternative was not included in the FS--an additional
groundwater study was recommended instead. The following discussion will
focus on the final evaluation of each alternative, including the no action
alternative, in consideration of relevant GWS information as well as the
short and 10n9 term effects of SARA criteria and the requirements of the
NCP. Table 6, found prior to the Recommended Alternative section, is a
summary of the environmental, technical, and public health considerations
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TABLE 4:
INITIAL SCREENING Of TECHNOLOGIES
TREA'DtfNr
STA1\.5
PHIOR 10 G.S
~ FOR R£JOCTI~
ISOlATIOO
f Encapsulate the shallow' .1fer with
a surface caWl iner, cl.. bott.aD and
,
o grout wrtain sides
He ject.ed
Ineffective as continuous low
peDmeabi!ity barrier.
o sheet pile sides
He ject.ed
Steel is IIDSt econanical, but
corrodes with acidity.
o slurry wall sides
Acceptable
IN-SITU
Olanical or Biological Agents degrade,
rEIIDve, or iAmJbilize contaminants.
Unacceptable
Treatment agent must be contaninar.t
specific to avoid new toxic pnoducts.
~tWATER RtXDJERY
RalDw at least 5 vOlUDlitS of shallow
aquiter groundwater,
o No treatment with Deep ~ll Injection.
.
.
..
,
Acceptable
o Biological Treatment SystEm. with
Discharge and Deep WEtll Injection.
.
Acceptable
o Carbon Adsorption 5ystED.. with
Discnarge and Deep WEtll Injection.
*
Acceptable
.'lbis systan canprised of CT) chelDical precipitation, (2) activated sludge, (3) partial discharge/dis~sal.
..Canprised ot (1) multi-media filtration, (2) carbon adsomtion, (3) reverS4! OSIIOsis, (4) partial diSCharye' . 'Jx>sal.
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""
16
TABLE S: GROUNDWATER FS ALTERNATIVES COST SUMMARY
REMEDIAL
AL TERNATIVES
CAP IT AL
COSTS
ANNUAL O&M
PRESENT WORTH*
S I u r ry Wa I I $786,750 $82,500 $1,550,000
Containment System
Recovery/Offslte Dis~osal $38H, 125 $3,886,250 $15,120,000
Recov~ry/Onsi te $775,625 $284,250 $1,860,000
Bioloyical Treatment
Partial Discharye
and Offsite Disposal
Recovery/Ons i te $413,125 $1 ,1 t3, 7\0 $4,675,000
Carbon Treatment
Partldl Discharye
and Offsite Disposal
*BASIS:
0\ inflation rate; 10\ discount rate; 5 year life cycle, except for
slurry wall alternative -- 30 year life cycle used.
...
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17
ALTERNATIVE 1
Isolation of the Upper Aquifer: A slurry wall with a 2000 foot circumference,
a 3 foot width, and a 23 foot depth (5 feet into the clay aquitard, 18 feet
within the upper sand) was assumed adequate to contain the contaminant plume.
The clay aquitard was assumed to be impermeable. A cap 6 acres in size, consisting
of a Z foot clay layer with a synthetic liner, was also required.
From information presented in the GWS, contaminants have penetrated the clay
aquitard both vertically and horizontally. If a slurry wall were constructed,
lateral dispersion within the aquitard would be limited while vertical migration
could be intensified. Contaminants would have a higher potential for reaching
the middle aquifer. A synthetic liner between the upper sand and clay aquitard
is technically infeasibl~. Therefore, the slurry wall remedial alternative has
been rejected due to unreliable effectiveness.
ALT ERNAT I VE 2
Groundwater Recovery & Offsite Disposal: The shallow aquifer holds 11.5 million
gallons of groundwater beneath the site. In consideration of aquifer character-
istics and the affinity for adsorption of contaminants of concern, 'approximately
5 times this amount would need to be removed in order to..cleanse the pore spaces'
of contaminants present. A configuration of 35 shal16w wells on 60-foot centers
could withdraw groundwater at 50,400 gallons/day (gpd). These wells would then
discharge through a polypropylene piping system to a centrally located holding
tank. After pH adjustment, the liquid waste could be transported to a local deep
well injection field for disposal.
About 300 days were estimated to remove 11.5 million gallons, assuming service
time for each well at varying times. Therefore. any recovery process was assumed
to take a minimum of 5 years. During this time. any offsite disposal alternative
would create a potential exposure route. Access roads to and from the site pass
directly through a residential neighborhood.
The GWS uses a slightly more conservative estimate for the number of times
the pore spaces should be flushed in order to remove contaminants of concern
from the shallow aquifer-eat least 6 volumes are necessary. Even this amount
of time might prove inadequate to remove the contaminants lying in the lower
sediments 0' the upper sand saturated zone. Possibly a 7- to 9-year period
would be required fo~ groundwater reclamation through this alternative.
Since 1001 of the contamination is merely moved to a different location. the
effectiveness of this non-treatment remedy falls below that of similar treatment
alternatives which could permanently and significantly reduce the toxicity.
mObility. or volume of contaminants. Furthermore. this alternative would not
comply with the 1986 Land Disposal Restrictions which require treatment of
contaminated water down to specified levels prior to deep well injection
(Land Disposal Restrictions effective for Superfund sites November 8.1988).
.. .
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v
18
ALTERNATIVE 3
Groundwater Recover, Onsite 8iolo
he groundwater recovery system is
The Biological System would utilize chemical precipitation followed by a conven-.
tional activated sludge unit. The sludge generated by both these steps would
total 3% of the contaminated groundwater feed stream.- The sludge was assum~
to be withdrawn at a sufficient flow rate to keep the solids content below the
upper limit allowable at deep well disposal sites. Final filtration was assumed
unnecessary and was not included in the FS cost analysis. The remaining 97%
could be discharged as adequately treated water. Although the entire process
must be continuous (24 hour operation/day), the pumping limit of the shallow
aquifer remains about 50,DOO gpd. Therefore, the cleanup would last the same
number of years required for groundwater recovery.
The 1986 Land Disposal Restrictions would apply to deep well injection disposal.
In addition, any discharged water would be required to meet the limits imposed
by the National Pollutant Discharge Elimination System.
In any groundwater recovery alternative, the length of time required for final
aquifer cleanup is of major consequence. Ar onsite groundwater treatment
alternative would transport less volume offsite than the~lOOl disposal option,
but such an alternative would present potential hazards fOr area residents and
for the surface environment. Shallow groundwater pumped to the surface would
create a potential direct exposure risk to contaminants over an extended time
period of 7 to 9 years, perhaps longer. The floodplain area, with the continued
subsidence, offers little stability for a long term onsite treatment remedy.
ALTERNATIVE 4
. The Carbon System would utilize multi-media filtration followed by carbon
adsorption treatment and reverse osmosis. About 80S of the waste stream could
be discharged as adequately treated water while the remaining 201 would require
deep well injection. The system would operate on an 8 hour day cycle for the
same number 0' ,.ars required for groundwater recovery.
-
The 1986 Land Dtsposal Restrictions would apply to deep well injection disposal
and to the disposal of spent carbon. Any discharged water would be required to
meet the limits imposed by the National Pollutant Discharge Elimination System.
Concern over a potential direct exposure from onsite treatment also applies to
the carDon adsorption remedy, as discussed above under alternative 3. During
flooding, the batch system might pose less hazards than the biolo~ical system
continuous operation. However, the difference is insignificant when comparing
effectiveness and technical imp1ementabi1ity.
-
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l~
ALTERNATIVE 5
No Action with Groundwater/Surface Envirorrnent Moni tori~: Table 7 is a sllmlary
of specifications for groundwater aoo surtace water rronitorirrJ. The shallow
aquiter roonitori~ is necessary to track the attenuation ~rocess. As a protective
measure, the middle aquifer should also be roonitored. It contamination does
break through the clay aquitard, corrective action can be initiated before
levels of concern are reached. Similarly, sediment aM surtace water samples
are reccmnenaed for the sana pits, Grennel Slough, and Clear Lake to ensure
that contaminants do not impact the sUrroundiBJ surface area. MonitoritYJ should
begin imnediately upon canpletion ot the source removal. Table ij is a detailed
breakaown ot roonitorirrJ costs for this alternative.
It canbined with a long term roonitoring prCXJram, a no action remedy \«)uld not
pose technical, envirorrnental, or health considerations (Table 6) given the
current available site data. Any future risk of exposure tor the surrounding
area residents aoo the surface environment is anticipated to be less than that
risk associated with ~roundwater recovery alternatives due to site-specitic
characteristics.
-
Appl icable, Relevent, and Appropriate Requirements for the Selected Rsnedy
SARA emphasizes the importance of ARARS in selection ot the remedial action.
Site-specific coooitions were considered when reviewing ~rounawater and surface
envirorrnent standards to determine the need for corrective action. Water Quality
Criteria were used to evaluate the effect of u~r aquifer contaminants in the
surface waters at Highlands due to the hydrologic connection with the upper
aquifer. Maximun COntaminant Level concentrations were used tor the deeper
groundwaters beneath the upper sand at Highlands. StaOOards have not been
established tor contaninants of concern within sediments of the surface water
boc1ies or within sediments ot underlyiRj strata. lheretore, tJ'X)se concentrations
of contaminants detected were caapared to background level.s specific to the
Highlarxis area. Since contaninants of concern were not detected above correspoooil'„J
criteria in any of the surt:ace water bodies or deeper aquiters, a no action
rEmedy with l~ tem monitori~ is feasible tor the Highlaoos site.
...
t'-
SARA criteria toIr~~ial alternatives emphasizes the requirement for peImanent
and significant ~1Q'1 of toxicity, IOObility, or VOlUDe ot contaninants.
However, this criteria must also be balanced with the short and long teen eftects
ot the remedy. n. groundwater recovery alternatives \«)uld present potential
exposure pathways for area residents and the surrounding envirorment over a
seven to nine year period. 'Ihe oon-treatment/offsite disposal alternative can
not be considered due to ooncanpliance with the 1986 Land Disposal Restrictions
tor deep well inJection. 'Ihe treatment systems with discharge/otfsite disposal
~ld accanplish the sane erxi result as the 00 action remedy with lOBJ teen
ooni torinJ.
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v
'-'
AL TEf
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21
TABLE 7: RECOMMENDED ALTERNATIVE---NO ACTION WITH MONITORING
TYPE OF MINIMUM FREQUENCY TYPE OF
RECOMMENDED NUMBER OF MONITORED ANALYSIS FOR
MON ITOR I NG LOCAT IONS PER YEAR EACH LOCATIONS
.Upper Aquifer Wells 3 Fi rst Year: 4 Full HSL Scan
plus pyridine
Thereafter: 1
Middle Aquifer Wells
4
1
GW Quality plus
Inorganics/Organics
.
.
"-
.
Grenne 1 Slough,
Cl ear Lake, a"d
the Sand Pits:
1
(for each)
1
For each type of
of sample:
(1) Surface Water Samples
(2) Sediment Samples
(1) Inorganics Only
(2) Benzene, Pyr id i r.e,
and Inorganics
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u
u
22
"TABLE 8: DETAILED COST B~£AKDOWN FOR
. THE NO ACTION REMEDY WITH MONITORING
ACTIVITY
ANNUAL COSTS ($)
GW Monitori ng*
Collection of Samples
Sample Analysis
Administrative
1st Year Only
560
6, 380
800
Years 2-30
Subtotal for Groundwater Monitoring
7, 740
200
3, 080
320
3,600
SW Monitoring
Surface Water Analysis
Sediment Analysis
Collection & Administration (10% of Analysis total)
Years 1-30
525
2,550
"300
Subtotal for Surface Monitoring
..
.
".
3,375
Total Cost of Monitoring for the first year =
Total Annual Cost for the remaining 29 years =
Present Worth Value** for Total Cost
$11,120
$ 6,980
$69, 730
=
*Groundwater monitoring costs are estimated by the same equations outlined in
the current Operating Plan for the Highlands source operable unit. Four wells
in the upper aquifer are used for simplification of cost analysis instead of
the minimum requirement of three.
**This value does not account for" those funds already allocated within the
Operating Plan referenced above. Basis: 0% inflation rate; 10 , discount rate;
30 year period. .
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23
RECOMMENDED ALTERNATI~E
~ Term Monitoring Program: A No Action Remedy with monitoring of the
surface environment and groundwater is recommended for the Highlands site.
After about 30 years of existence at the Acid Pit Jocation, organics and
inorg~nics have impacted the shallow aquifer beneath the site (unused water
zone), but have not affected the San Jacinto River, Grennel Slough, Clear lake,
or deeper groundwaters. The sand pits have been in existence for 15 years.
Contaminants of concern have not been detected in recent sampling events.
Once the Source removal is complete, the contaminant migration to the shallow
aquifer will be significantly reduced. The natural flow of groundwater in
this aquifer will dispers~ those contaminants already present and will allow
attenuation of contaminants within the clay aquitard. The middle aquifer
should not be affected by contaminants already present in the shallow aquifer
and the clay aquitard.
The groundwater monitoring wells are currently in place due to the 1984 ROD
requirements. The current Operating Plan for Highlands Remedial Action Project
(dated February 13, 1987) estimates ~O per year for groundwater monitoring
costs. This estimate is based upon semi-annyal monitoring of 8 wells. Over
a 30 year period with a 10% discount rate, the presen~ w~th value for total
monitoring costs is $60,502. This money is already funded under the Source
control ROD of 1984 for the Highlands site.
Additional costs for the surface water and sediment sampling, pJus the changes
due to groundwater monitoring frequencies, totals $4,700 for the first year
and $560 per year for the remaining 29 years. For the purpose of comparative
cost analysis~ four monitor wells for the upper aquifer were used instead of
the minimum requirement of three. The present worth value for total additional
costs of monitoring over the entire 30 year period is estimated at $10,000.
OPERATION & MAINTENANCE
, Implementation of the long term monitoring program for the groundwater operable
unit will be part of the operation and maintenance plan for the source operable
unit. Refer to the 1984 ROD for other post-closure activities on site.
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u
ATTACHMENT I
Health Assessment for
Highlana Acid Pit
Groundwater Operable Unit
by
Agency for Toxic Substances
and Disease Registry
March 5, 1987
-
..
..
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(#
DEPARTMENT OF HEA~ TH & HUMAN SERVICES
Public Health Service
Agency for Toxic Substances
and Disease Registry
Atlanta GA 30333
Ma rch 5, 1987
MEMORANDUM
SUBJECT:
Groundwater Study, Highlands Acid Pits Site
Highlands, Texas SI-87-136
FROM:
Senior Public Health Advisor
Regional Office for Health Response
ATSDR/EPA-6
TO:
Cynthia J. Adudde11
Texas Remedial Section (6H-ST)
...
"
The Agency for Toxic Substances and Disease Registry (ATSDR) has
been requested to review and evaluate the document "Final Report for
Highlands Acid Pit, Highlands, Texas - Groundwater Contamination Evaluation,
February 1987." Based on the document the United States Envi ronmenta1
Protection Agency (USEPA), Region VI is recommending that the middle
aquifer at the site and nearby sand pits be monitored for organics on a
yearly basis after completion of the proposed remedial action.
The conclusions and recommendations presented have been developed
with the assistance and concurrence of ATSDR, Health Assessments Branch.
BACKGROUND
The Highlands Acid Pit Site is located approximately 1.4 miles west
of Highlands. Texas on a. peninsula bordered by wooded areas to the north,
Grenne1 Slou~ to the west, Clear1ake to the south, and ponds and flooded
. sand p its to tile elSt. Dumping is felt to have started at the site in
1951 and consist primarily of refinery sludges.
As part of the USEPA Record of Decision for the site, contaminated
soil and sediment above the water table will be removed and replaced with
clean fill. This will reduce contaminated surface runoff to the surrounding
surface waters and downward migration into groundwater sources. Beneath
the site are three sand intervals forming shallow, middle and deep aquifers
separated by two clay aquitards. Organic and inorganic contaminants have
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v
2
been found in the sh~llow aquifer and organic contaminants have migrated
into the aqui~ard separating the shallow and middle aquifers. Contaminants
of concern have been identified as-organics: benzene and pyridine; inorganics:
cadmium, chromium ana lead.
The San JacintJ ~iver and the upper sand aquifer are hydraul ically
connected. Groundwater in the Houston region is furnished by the Chicot
and Evangeline Aquifers. The middle and lower sand aquifers are in the
Chicot Aquifer.
ENVIRONMENTAL PATHWAYS
Groundwater migration of contaminants to the surrounding surface
waters and downward migration toward the middle aquifer are the primary
pathways of conern. Shauld contamination of surrounding surface waters
occur, then concern would also exist over the possibility of aquatic
contamination.
HUMAN PATHWAYS
Of principle concern would be the potential for ingestion/contact
with contaminated potable water, potential contact with contaminated
surface water through recreation activities (i.e., swimming), and consumption
of potentially contaminated fish from the surrounding s.urface waters.
DISCUSSION
.
.
".
1.
Groundwater
Seven monitoring wells in the shallow aquifer (5-25 feet) identified
low pHs, high total dissolved solids and high benzene levels. There
appears to be differences in the concentrations reported in Exhibit 4-3
and Exhibit 5-1 for shallow aquifer monitoring. This may reflect
differing sampling periods, however, Exhibit 5-1 does not indicate when
sampling occurred. Likewise, p.5-4, para. 5-2, indicates the highest
concentration for benzene as being 148 mg/l while Exhibit 5-1 indicates
the high as 52 mg/l and Exhibit 4-3°as 210 mg/l. Several metal concentrations
in the shallow aquifer also exceeded acceptable levels. It was reported
that no public wells are drawing water from the shallow aquifer.
Three monitoring wells in the deep aquifers (greater than 60 feet
. deep) were reported as having acceptable pHs and benzene levels, but
elevated leY.1s.of~anganese and lead. Eleven water wells were identified
as being located within a two mile radius of the site and in the Chicot
Aquifer (some confusion exists in the reporting, p.2.3., para. 2.4,
reports the wells within 2 miles while ~.6.8, para 6.3, reports them within
one mile). The nearest residential well was one-half mile north of the
site and located in the middle aquifer. Site contaminants were not
evident in samples from this well. Based on the information provided, it
does not appear that the middle or lower aquifers have been affected by
contaminants from the site.
2.
Aqu itard
Borings have identified benzene migration downward into the aquitard
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3
Migration has greatly exceeded that predicted OJ theoretical calculations
and 1 ikely is re1ated.to ~1 ic~ensjdes. I~organic migration does not
appear to represent a problem.
3.
Surface Waters
Benzene has not been detected in surface water samples taken in Gennel
Slough, Clear lake or the sand pits. Other organics and inorganics were
within acceptable ranges. Concentrations of organics and inorganics in
sediment samples taken in the same locations were not exceptional and for
inorganics, within normal background ranges.
On p.6-4 and 6-5 it is speculated that inorganic migration has
occurred, and probably fo~ some time, to the surrounding surface waters
and that the lack of elevated concentrations in surface waters and sediments
would indicate that inorganic contaminants pose no threat through this
pathway. However. this is based on the calculated velocity of the ground-
water, without the constraints of retardation of the contaminants, and
limited sampling results. Information provided does not support the
assumption that the maximum concentration of inorganic contaminants has
reached the surrounding surface waters and represent no potential hazard.
On p. 6-7 it is indicated that the benzene travel time to the sand
pits ar~a is 23 years. This would indicate it shoul~.haYe already reached
this area regardless of the fact that the pits have only existed 15 years.
4.
Contaminated Waste
The total est~mated volume of waste at the site is 77,428 yd3 (p.2-4).
Of this 18,703 yd 1ij above the water table and will be removed. However,
this leaves 58,725 yd of untreated waste. While the relative distribution
of contaminants (i.e., benzene) in the areas above and below the water
table has not been identified, the potential exists that the proposed
remedial action will remove only approximately 25' of the problem. The
remaining 75' could continue to impact through the shallow aquifer on the
surrounding surface waters and the aquitard.
CONCLUSION
Organic and inorganic contamination exists in the shallow aquifer;
"however, since it is not used as a potable water source, it only presents
a problem to the extent it contaminates lower aquifers and surrounding
surface waters. The lower aquifers appear uncontaminated at this time.
Benzene migration through the aquitard, because of the uncertainty
associated with its migration rate, represents some potential for future
contamination of the middle aquifer. This potential should be followed.
Cont aminat ion of surrounding s~rf ace waters above acceptabl e concentrat ions
was not identified through the sampl ing conducted. However, the assumption
that contaminants have reached these areas and been effectively diluted
was not adequately supported. Monitoring should be continued to support
this assumption.
...
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l./
v
4
RECOMMENDATIONS
1.
Monit0ring of t~e middle aquifer should be continued on a periodic basis.
2. . Monitoring of the three surrou~ding surface waters and associated
sediments should be continued on a periodic basis.
"
.
I / ..' I
,. I ./ ,'-; I
~ . ~ , . / .. . , .....'
~...'..I, .... '. -... (. .I""'
\<
.\ '
Carl R. Hickam, R.S.
".
".
..
'.
...
_.
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9.
ATTACHMENT II
Responsiveness Summary for
. Highlands Acid Pit
Groundwater Operable Unit
~.
~
"-
by
Environmental Protection Agency
Region VI
May 27, 1987
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G
R£SPONSIVENESS SUMMARY
Highlands Acid Pit
Groundwater Op~rable Unit
This Communitj Relations Responsiveness Summary is divided into the following
s~ctions:
[ .
Conc~rns rdised prior to the Groundwater Study Public Comment Period.
Concerns raised during the Groundwater Study Public Comment Period.
I I .
[ 11.
V I.
Response to Comm~nity Concerns.
Remaining Concerns.
1.
Concerns raised prior to th~ Groundwater Study Public Comment Period.
The Highlands Acid Pit site was broken into two operable units for remedial
dctlvities. The source control remedy was determined in the 1984 Record
of Decision (ROD) to include: {I) excavation of waste and contaminated
soil over a 2.41 acre dr~d down to the water tab~, ~2) transportation of
excavdted materials to a permitted class 1 disposal facility, (3) clean
fil I for the excavated area, (4) installation of a groundwater monitoring
system, (5) site maintenance and groundwater monitoring for a 30 year period.
Thos~ issues raised during the source operable unit public comment period
can be found in the 1984 ROD Summary, Attachment I, Community Relations.
Conc~rns raised during the Groundwater Study Public Comment Period.
I I.
Copies of the Feasibiltiy StUdy Report (FS) and copies of the Groundwater
Study Report (GWS) were sent to repositories prior to the press release
of the proposed remedial action, May 6, 1987, for the groundwater
operable unit. A copy of tn~ fact sheet is also on file. The public
meeting was held in Highlands, Texas on May 12, 1987. The Texas Water
Commision yave a brief presentation on the current status of the source
removal action onsite. The Environmental Protection Agency (EPA) presented
GWS results. identified remedial alternatives considered from the FS, and
discuSSed the details of the proposed remedial action -- no action with
long ten. mQ~1tQr1ng. Comments expressing satisfaction with the remedy
were made during and after the public meeting. Questions were answered in
relation to tne following topics:
o Once tne cu~rent source control remedy is completed, what effect
will the site have on property values for area residents?
o
Is a lawsuit p~nding againist the Highlands site?
. 0 Could an infant's illness be caused by the site?
o Were tne original wastes assumed to be industrial in nature, or
were tney tracked down to origin?
o
_. -
If residents use the city's water, do they need to worry? What is
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2
II. (continued)
About 2U peopr~ were present at the public meeting. No written comments
w~re received durin~ the public comment period, May 6 through May 27, 1987.
Howev~r, som~ conc~rn over the lack of sdmpling in the southeast ar~a of
the site (Clear Lake area) was expr~ssed by Brad Christensen of Highlands,
Texas. Mr. Christ~ns~n yrew u~ in the area and had valid reasons for this
concern. See section IV for follow-up actions.
III. Response to Community Concerns
Th~ specific r~sponses to the above listed topics can be found in the public
transcript on file in the EPA Region VI office. The following synopsis
is repres~ntative of this trdnscript.
o Once the current source control is completed, the EPA cannot say that
property values would increase. The agency has no influence over property
values near Superfund sites.
o No lawsuit is currently pending against Highlands. If a viable potentially
responsible party had been found, the EPA would follow up for cost recovery,
even after the r~edial action is completed.
o The infant's illness can not be attributed to the.Highlands site unless
the infant had b~en onsite. No contaminants h.ye ~een detected offsite.
Adequate fencing and site security is an important aspect of the remedial
action. The agency has strived for the maximum protection possible.
"
o The orlginal source of the waste sludge"is unknown. However, the
contaminants are characteristic of industrial waste resulting from refinery
processes.
o The Highlanas city water Should not be affected by the Highlands site.
The EPA has established the area of influence in relation to the site,
and as previously noted, the documented wells in that ared draw water from
the lower aquifer. Only one well is screened in the middle aquifer and
tnat wel I 1s 1n the opposite d1rection of contaminated groundwater flow.
The last to~ic, in reference to the source of the city's drinking water supply,
is addressed more fully by ;nfonnat;on rece;ved from the Harr;s County Health
Department (correspondence dated May 14, 1987):
The"i-ir. two water supplies for the Highlands area:
Harr1s County Water Control & Improvement District 11
which has about 2,OUO connections serving most of the
HighlandS area and Harris County Fresh Water Supply
District 118 which serves the remaining 200 con-
nections southeast of Highlands along Jones Road.
Both water districts use a combination of well water
and surface water. Surface water ;s obtained from
th~ Bay town Area Water Authority plant on Thompson
Road, which treats Trinity River Water. Fresh Water
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3
III. (continued)
Sup~ly Disteict 116 has one wat~r well located at
1721 Jones Road which is 480 feet deep. Water Control
and Improvement Uistrict #1 nas three (3) 500 feet
deep wells to augment their surface water supplies.
CnemiCdl dnalysls for botn surface water and well water were also submitted to
the EPA. Th~ water quality is adequate for drinking water and domestic purposes.
No contamination was detected in any of the water samples.
IV.
Remaining Concerns
The southeast portion of the site. beyond the excavation area. has experienced
excessive erosion & subsequent runoff to Clear Lake. Flow patterns as described
by Mr. Christensen were previ ously documented by a Texas Department of Water
Resources interoffice memorandum. on file at the EPA Region VI office. correspondece
dated May B. 19B4.
To detenmine if contamination was carried with flooded sediments into Clear Lake,
EPA Region VI plans to sample the southeast portion of Clear Lake. Previous
sampllng of this area was not completed since tne southern portion .of the site
did not show contamination.
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'tiXAS WATER COMMISSION
-
Paul Hopkin.. ChIiimMI' .
Ralph RonWlt. C4m.-'nfl...r
John O. Houchiu, Camml88iOner
C. Martin Wi180n m. General Couna
J..... k. Rourke. Jr., Chief ExamiM\
M8ry Ann Hefner, Chief Clerk
tarl\l R. Soward, Execl.ltive Director
June 26. 1987
Mr. Robert I. LaYton, Jr., p.!.
Regional Admini.trator
U. S. Environmental Protection Agency
Region VI"
1445 Ro.. Avenue
Dalla., Texa. 75202-2733
Re:
Draft Abbreviated Record of Decision
Highland. Acid Pit Groundwater Operable Unit
Dear Mr. Layton:
.,
We have reviewed the propoeed Draft Abbreviated Record of
Decision (ROD) and respensivene.. summary for the Highlands
Acid Pit. Groundwater Operable unit.
Weh.ve no objection to the is.uance of a ROD by the
Environmental Protection Agency (B'A). Before the State of
Xexa. can concur by providing it. 10' share of the COlt for
the selected remedial alternative, the fiscal impact of this
action mu.t be evaluated and SUb.equently coordinated with
.tate'. budgetary proce.8.
On a related matter, we would like to comment on the
obligation of State monie. tor a periOd of 30 years after
the r8ll8dial COft.truction activit1.. Ir. cOIII»l.te. Such a
a088tt88Dt by the State of Texa. may be a violation of
5"" .VIII, Section 6 of the Texa. COn8titution which
a '. .tAe appropriation of money beyonc1 . two year
peri " -
Sincerely,
.~~
Larry R. Soward
Executive Direc~or
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